Rang on the phone and gave the game away (4)
I believe the answer is:
told
'gave the game away' is the definition.
(I've seen this in another clue)
'rang on the phone' is the wordplay.
'rang' becomes 'tolled' (tolling is a kind of ringing).
'on the phone' shows a homophone (sound like).
'tolled' sounds like 'TOLD'.
'and' acts as a link.
(Other definitions for told that I've seen before include "Assured" , "Said" , "Made an impact" , "instructed" , "Authorised - broadcast" .)